diff options
Diffstat (limited to 'net/batman-adv/routing.c')
| -rw-r--r-- | net/batman-adv/routing.c | 1273 |
1 files changed, 1273 insertions, 0 deletions
diff --git a/net/batman-adv/routing.c b/net/batman-adv/routing.c new file mode 100644 index 000000000..83f31494e --- /dev/null +++ b/net/batman-adv/routing.c @@ -0,0 +1,1273 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (C) B.A.T.M.A.N. contributors: + * + * Marek Lindner, Simon Wunderlich + */ + +#include "routing.h" +#include "main.h" + +#include <linux/atomic.h> +#include <linux/byteorder/generic.h> +#include <linux/compiler.h> +#include <linux/errno.h> +#include <linux/etherdevice.h> +#include <linux/if_ether.h> +#include <linux/jiffies.h> +#include <linux/kref.h> +#include <linux/netdevice.h> +#include <linux/printk.h> +#include <linux/rculist.h> +#include <linux/rcupdate.h> +#include <linux/skbuff.h> +#include <linux/spinlock.h> +#include <linux/stddef.h> +#include <uapi/linux/batadv_packet.h> + +#include "bitarray.h" +#include "bridge_loop_avoidance.h" +#include "distributed-arp-table.h" +#include "fragmentation.h" +#include "hard-interface.h" +#include "log.h" +#include "network-coding.h" +#include "originator.h" +#include "send.h" +#include "soft-interface.h" +#include "tp_meter.h" +#include "translation-table.h" +#include "tvlv.h" + +static int batadv_route_unicast_packet(struct sk_buff *skb, + struct batadv_hard_iface *recv_if); + +/** + * _batadv_update_route() - set the router for this originator + * @bat_priv: the bat priv with all the soft interface information + * @orig_node: orig node which is to be configured + * @recv_if: the receive interface for which this route is set + * @neigh_node: neighbor which should be the next router + * + * This function does not perform any error checks + */ +static void _batadv_update_route(struct batadv_priv *bat_priv, + struct batadv_orig_node *orig_node, + struct batadv_hard_iface *recv_if, + struct batadv_neigh_node *neigh_node) +{ + struct batadv_orig_ifinfo *orig_ifinfo; + struct batadv_neigh_node *curr_router; + + orig_ifinfo = batadv_orig_ifinfo_get(orig_node, recv_if); + if (!orig_ifinfo) + return; + + spin_lock_bh(&orig_node->neigh_list_lock); + /* curr_router used earlier may not be the current orig_ifinfo->router + * anymore because it was dereferenced outside of the neigh_list_lock + * protected region. After the new best neighbor has replace the current + * best neighbor the reference counter needs to decrease. Consequently, + * the code needs to ensure the curr_router variable contains a pointer + * to the replaced best neighbor. + */ + + /* increase refcount of new best neighbor */ + if (neigh_node) + kref_get(&neigh_node->refcount); + + curr_router = rcu_replace_pointer(orig_ifinfo->router, neigh_node, + true); + spin_unlock_bh(&orig_node->neigh_list_lock); + batadv_orig_ifinfo_put(orig_ifinfo); + + /* route deleted */ + if (curr_router && !neigh_node) { + batadv_dbg(BATADV_DBG_ROUTES, bat_priv, + "Deleting route towards: %pM\n", orig_node->orig); + batadv_tt_global_del_orig(bat_priv, orig_node, -1, + "Deleted route towards originator"); + + /* route added */ + } else if (!curr_router && neigh_node) { + batadv_dbg(BATADV_DBG_ROUTES, bat_priv, + "Adding route towards: %pM (via %pM)\n", + orig_node->orig, neigh_node->addr); + /* route changed */ + } else if (neigh_node && curr_router) { + batadv_dbg(BATADV_DBG_ROUTES, bat_priv, + "Changing route towards: %pM (now via %pM - was via %pM)\n", + orig_node->orig, neigh_node->addr, + curr_router->addr); + } + + /* decrease refcount of previous best neighbor */ + batadv_neigh_node_put(curr_router); +} + +/** + * batadv_update_route() - set the router for this originator + * @bat_priv: the bat priv with all the soft interface information + * @orig_node: orig node which is to be configured + * @recv_if: the receive interface for which this route is set + * @neigh_node: neighbor which should be the next router + */ +void batadv_update_route(struct batadv_priv *bat_priv, + struct batadv_orig_node *orig_node, + struct batadv_hard_iface *recv_if, + struct batadv_neigh_node *neigh_node) +{ + struct batadv_neigh_node *router = NULL; + + if (!orig_node) + goto out; + + router = batadv_orig_router_get(orig_node, recv_if); + + if (router != neigh_node) + _batadv_update_route(bat_priv, orig_node, recv_if, neigh_node); + +out: + batadv_neigh_node_put(router); +} + +/** + * batadv_window_protected() - checks whether the host restarted and is in the + * protection time. + * @bat_priv: the bat priv with all the soft interface information + * @seq_num_diff: difference between the current/received sequence number and + * the last sequence number + * @seq_old_max_diff: maximum age of sequence number not considered as restart + * @last_reset: jiffies timestamp of the last reset, will be updated when reset + * is detected + * @protection_started: is set to true if the protection window was started, + * doesn't change otherwise. + * + * Return: + * false if the packet is to be accepted. + * true if the packet is to be ignored. + */ +bool batadv_window_protected(struct batadv_priv *bat_priv, s32 seq_num_diff, + s32 seq_old_max_diff, unsigned long *last_reset, + bool *protection_started) +{ + if (seq_num_diff <= -seq_old_max_diff || + seq_num_diff >= BATADV_EXPECTED_SEQNO_RANGE) { + if (!batadv_has_timed_out(*last_reset, + BATADV_RESET_PROTECTION_MS)) + return true; + + *last_reset = jiffies; + if (protection_started) + *protection_started = true; + batadv_dbg(BATADV_DBG_BATMAN, bat_priv, + "old packet received, start protection\n"); + } + + return false; +} + +/** + * batadv_check_management_packet() - Check preconditions for management packets + * @skb: incoming packet buffer + * @hard_iface: incoming hard interface + * @header_len: minimal header length of packet type + * + * Return: true when management preconditions are met, false otherwise + */ +bool batadv_check_management_packet(struct sk_buff *skb, + struct batadv_hard_iface *hard_iface, + int header_len) +{ + struct ethhdr *ethhdr; + + /* drop packet if it has not necessary minimum size */ + if (unlikely(!pskb_may_pull(skb, header_len))) + return false; + + ethhdr = eth_hdr(skb); + + /* packet with broadcast indication but unicast recipient */ + if (!is_broadcast_ether_addr(ethhdr->h_dest)) + return false; + + /* packet with invalid sender address */ + if (!is_valid_ether_addr(ethhdr->h_source)) + return false; + + /* create a copy of the skb, if needed, to modify it. */ + if (skb_cow(skb, 0) < 0) + return false; + + /* keep skb linear */ + if (skb_linearize(skb) < 0) + return false; + + return true; +} + +/** + * batadv_recv_my_icmp_packet() - receive an icmp packet locally + * @bat_priv: the bat priv with all the soft interface information + * @skb: icmp packet to process + * + * Return: NET_RX_SUCCESS if the packet has been consumed or NET_RX_DROP + * otherwise. + */ +static int batadv_recv_my_icmp_packet(struct batadv_priv *bat_priv, + struct sk_buff *skb) +{ + struct batadv_hard_iface *primary_if = NULL; + struct batadv_orig_node *orig_node = NULL; + struct batadv_icmp_header *icmph; + int res, ret = NET_RX_DROP; + + icmph = (struct batadv_icmp_header *)skb->data; + + switch (icmph->msg_type) { + case BATADV_ECHO_REQUEST: + /* answer echo request (ping) */ + primary_if = batadv_primary_if_get_selected(bat_priv); + if (!primary_if) + goto out; + + /* get routing information */ + orig_node = batadv_orig_hash_find(bat_priv, icmph->orig); + if (!orig_node) + goto out; + + /* create a copy of the skb, if needed, to modify it. */ + if (skb_cow(skb, ETH_HLEN) < 0) + goto out; + + icmph = (struct batadv_icmp_header *)skb->data; + + ether_addr_copy(icmph->dst, icmph->orig); + ether_addr_copy(icmph->orig, primary_if->net_dev->dev_addr); + icmph->msg_type = BATADV_ECHO_REPLY; + icmph->ttl = BATADV_TTL; + + res = batadv_send_skb_to_orig(skb, orig_node, NULL); + if (res == NET_XMIT_SUCCESS) + ret = NET_RX_SUCCESS; + + /* skb was consumed */ + skb = NULL; + break; + case BATADV_TP: + if (!pskb_may_pull(skb, sizeof(struct batadv_icmp_tp_packet))) + goto out; + + batadv_tp_meter_recv(bat_priv, skb); + ret = NET_RX_SUCCESS; + /* skb was consumed */ + skb = NULL; + goto out; + default: + /* drop unknown type */ + goto out; + } +out: + batadv_hardif_put(primary_if); + batadv_orig_node_put(orig_node); + + kfree_skb(skb); + + return ret; +} + +static int batadv_recv_icmp_ttl_exceeded(struct batadv_priv *bat_priv, + struct sk_buff *skb) +{ + struct batadv_hard_iface *primary_if = NULL; + struct batadv_orig_node *orig_node = NULL; + struct batadv_icmp_packet *icmp_packet; + int res, ret = NET_RX_DROP; + + icmp_packet = (struct batadv_icmp_packet *)skb->data; + + /* send TTL exceeded if packet is an echo request (traceroute) */ + if (icmp_packet->msg_type != BATADV_ECHO_REQUEST) { + pr_debug("Warning - can't forward icmp packet from %pM to %pM: ttl exceeded\n", + icmp_packet->orig, icmp_packet->dst); + goto out; + } + + primary_if = batadv_primary_if_get_selected(bat_priv); + if (!primary_if) + goto out; + + /* get routing information */ + orig_node = batadv_orig_hash_find(bat_priv, icmp_packet->orig); + if (!orig_node) + goto out; + + /* create a copy of the skb, if needed, to modify it. */ + if (skb_cow(skb, ETH_HLEN) < 0) + goto out; + + icmp_packet = (struct batadv_icmp_packet *)skb->data; + + ether_addr_copy(icmp_packet->dst, icmp_packet->orig); + ether_addr_copy(icmp_packet->orig, primary_if->net_dev->dev_addr); + icmp_packet->msg_type = BATADV_TTL_EXCEEDED; + icmp_packet->ttl = BATADV_TTL; + + res = batadv_send_skb_to_orig(skb, orig_node, NULL); + if (res == NET_RX_SUCCESS) + ret = NET_XMIT_SUCCESS; + + /* skb was consumed */ + skb = NULL; + +out: + batadv_hardif_put(primary_if); + batadv_orig_node_put(orig_node); + + kfree_skb(skb); + + return ret; +} + +/** + * batadv_recv_icmp_packet() - Process incoming icmp packet + * @skb: incoming packet buffer + * @recv_if: incoming hard interface + * + * Return: NET_RX_SUCCESS on success or NET_RX_DROP in case of failure + */ +int batadv_recv_icmp_packet(struct sk_buff *skb, + struct batadv_hard_iface *recv_if) +{ + struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface); + struct batadv_icmp_header *icmph; + struct batadv_icmp_packet_rr *icmp_packet_rr; + struct ethhdr *ethhdr; + struct batadv_orig_node *orig_node = NULL; + int hdr_size = sizeof(struct batadv_icmp_header); + int res, ret = NET_RX_DROP; + + /* drop packet if it has not necessary minimum size */ + if (unlikely(!pskb_may_pull(skb, hdr_size))) + goto free_skb; + + ethhdr = eth_hdr(skb); + + /* packet with unicast indication but non-unicast recipient */ + if (!is_valid_ether_addr(ethhdr->h_dest)) + goto free_skb; + + /* packet with broadcast/multicast sender address */ + if (is_multicast_ether_addr(ethhdr->h_source)) + goto free_skb; + + /* not for me */ + if (!batadv_is_my_mac(bat_priv, ethhdr->h_dest)) + goto free_skb; + + icmph = (struct batadv_icmp_header *)skb->data; + + /* add record route information if not full */ + if ((icmph->msg_type == BATADV_ECHO_REPLY || + icmph->msg_type == BATADV_ECHO_REQUEST) && + skb->len >= sizeof(struct batadv_icmp_packet_rr)) { + if (skb_linearize(skb) < 0) + goto free_skb; + + /* create a copy of the skb, if needed, to modify it. */ + if (skb_cow(skb, ETH_HLEN) < 0) + goto free_skb; + + ethhdr = eth_hdr(skb); + icmph = (struct batadv_icmp_header *)skb->data; + icmp_packet_rr = (struct batadv_icmp_packet_rr *)icmph; + if (icmp_packet_rr->rr_cur >= BATADV_RR_LEN) + goto free_skb; + + ether_addr_copy(icmp_packet_rr->rr[icmp_packet_rr->rr_cur], + ethhdr->h_dest); + icmp_packet_rr->rr_cur++; + } + + /* packet for me */ + if (batadv_is_my_mac(bat_priv, icmph->dst)) + return batadv_recv_my_icmp_packet(bat_priv, skb); + + /* TTL exceeded */ + if (icmph->ttl < 2) + return batadv_recv_icmp_ttl_exceeded(bat_priv, skb); + + /* get routing information */ + orig_node = batadv_orig_hash_find(bat_priv, icmph->dst); + if (!orig_node) + goto free_skb; + + /* create a copy of the skb, if needed, to modify it. */ + if (skb_cow(skb, ETH_HLEN) < 0) + goto put_orig_node; + + icmph = (struct batadv_icmp_header *)skb->data; + + /* decrement ttl */ + icmph->ttl--; + + /* route it */ + res = batadv_send_skb_to_orig(skb, orig_node, recv_if); + if (res == NET_XMIT_SUCCESS) + ret = NET_RX_SUCCESS; + + /* skb was consumed */ + skb = NULL; + +put_orig_node: + batadv_orig_node_put(orig_node); +free_skb: + kfree_skb(skb); + + return ret; +} + +/** + * batadv_check_unicast_packet() - Check for malformed unicast packets + * @bat_priv: the bat priv with all the soft interface information + * @skb: packet to check + * @hdr_size: size of header to pull + * + * Checks for short header and bad addresses in the given packet. + * + * Return: negative value when check fails and 0 otherwise. The negative value + * depends on the reason: -ENODATA for bad header, -EBADR for broadcast + * destination or source, and -EREMOTE for non-local (other host) destination. + */ +static int batadv_check_unicast_packet(struct batadv_priv *bat_priv, + struct sk_buff *skb, int hdr_size) +{ + struct ethhdr *ethhdr; + + /* drop packet if it has not necessary minimum size */ + if (unlikely(!pskb_may_pull(skb, hdr_size))) + return -ENODATA; + + ethhdr = eth_hdr(skb); + + /* packet with unicast indication but non-unicast recipient */ + if (!is_valid_ether_addr(ethhdr->h_dest)) + return -EBADR; + + /* packet with broadcast/multicast sender address */ + if (is_multicast_ether_addr(ethhdr->h_source)) + return -EBADR; + + /* not for me */ + if (!batadv_is_my_mac(bat_priv, ethhdr->h_dest)) + return -EREMOTE; + + return 0; +} + +/** + * batadv_last_bonding_get() - Get last_bonding_candidate of orig_node + * @orig_node: originator node whose last bonding candidate should be retrieved + * + * Return: last bonding candidate of router or NULL if not found + * + * The object is returned with refcounter increased by 1. + */ +static struct batadv_orig_ifinfo * +batadv_last_bonding_get(struct batadv_orig_node *orig_node) +{ + struct batadv_orig_ifinfo *last_bonding_candidate; + + spin_lock_bh(&orig_node->neigh_list_lock); + last_bonding_candidate = orig_node->last_bonding_candidate; + + if (last_bonding_candidate) + kref_get(&last_bonding_candidate->refcount); + spin_unlock_bh(&orig_node->neigh_list_lock); + + return last_bonding_candidate; +} + +/** + * batadv_last_bonding_replace() - Replace last_bonding_candidate of orig_node + * @orig_node: originator node whose bonding candidates should be replaced + * @new_candidate: new bonding candidate or NULL + */ +static void +batadv_last_bonding_replace(struct batadv_orig_node *orig_node, + struct batadv_orig_ifinfo *new_candidate) +{ + struct batadv_orig_ifinfo *old_candidate; + + spin_lock_bh(&orig_node->neigh_list_lock); + old_candidate = orig_node->last_bonding_candidate; + + if (new_candidate) + kref_get(&new_candidate->refcount); + orig_node->last_bonding_candidate = new_candidate; + spin_unlock_bh(&orig_node->neigh_list_lock); + + batadv_orig_ifinfo_put(old_candidate); +} + +/** + * batadv_find_router() - find a suitable router for this originator + * @bat_priv: the bat priv with all the soft interface information + * @orig_node: the destination node + * @recv_if: pointer to interface this packet was received on + * + * Return: the router which should be used for this orig_node on + * this interface, or NULL if not available. + */ +struct batadv_neigh_node * +batadv_find_router(struct batadv_priv *bat_priv, + struct batadv_orig_node *orig_node, + struct batadv_hard_iface *recv_if) +{ + struct batadv_algo_ops *bao = bat_priv->algo_ops; + struct batadv_neigh_node *first_candidate_router = NULL; + struct batadv_neigh_node *next_candidate_router = NULL; + struct batadv_neigh_node *router, *cand_router = NULL; + struct batadv_neigh_node *last_cand_router = NULL; + struct batadv_orig_ifinfo *cand, *first_candidate = NULL; + struct batadv_orig_ifinfo *next_candidate = NULL; + struct batadv_orig_ifinfo *last_candidate; + bool last_candidate_found = false; + + if (!orig_node) + return NULL; + + router = batadv_orig_router_get(orig_node, recv_if); + + if (!router) + return router; + + /* only consider bonding for recv_if == BATADV_IF_DEFAULT (first hop) + * and if activated. + */ + if (!(recv_if == BATADV_IF_DEFAULT && atomic_read(&bat_priv->bonding))) + return router; + + /* bonding: loop through the list of possible routers found + * for the various outgoing interfaces and find a candidate after + * the last chosen bonding candidate (next_candidate). If no such + * router is found, use the first candidate found (the previously + * chosen bonding candidate might have been the last one in the list). + * If this can't be found either, return the previously chosen + * router - obviously there are no other candidates. + */ + rcu_read_lock(); + last_candidate = batadv_last_bonding_get(orig_node); + if (last_candidate) + last_cand_router = rcu_dereference(last_candidate->router); + + hlist_for_each_entry_rcu(cand, &orig_node->ifinfo_list, list) { + /* acquire some structures and references ... */ + if (!kref_get_unless_zero(&cand->refcount)) + continue; + + cand_router = rcu_dereference(cand->router); + if (!cand_router) + goto next; + + if (!kref_get_unless_zero(&cand_router->refcount)) { + cand_router = NULL; + goto next; + } + + /* alternative candidate should be good enough to be + * considered + */ + if (!bao->neigh.is_similar_or_better(cand_router, + cand->if_outgoing, router, + recv_if)) + goto next; + + /* don't use the same router twice */ + if (last_cand_router == cand_router) + goto next; + + /* mark the first possible candidate */ + if (!first_candidate) { + kref_get(&cand_router->refcount); + kref_get(&cand->refcount); + first_candidate = cand; + first_candidate_router = cand_router; + } + + /* check if the loop has already passed the previously selected + * candidate ... this function should select the next candidate + * AFTER the previously used bonding candidate. + */ + if (!last_candidate || last_candidate_found) { + next_candidate = cand; + next_candidate_router = cand_router; + break; + } + + if (last_candidate == cand) + last_candidate_found = true; +next: + /* free references */ + if (cand_router) { + batadv_neigh_node_put(cand_router); + cand_router = NULL; + } + batadv_orig_ifinfo_put(cand); + } + rcu_read_unlock(); + + /* After finding candidates, handle the three cases: + * 1) there is a next candidate, use that + * 2) there is no next candidate, use the first of the list + * 3) there is no candidate at all, return the default router + */ + if (next_candidate) { + batadv_neigh_node_put(router); + + kref_get(&next_candidate_router->refcount); + router = next_candidate_router; + batadv_last_bonding_replace(orig_node, next_candidate); + } else if (first_candidate) { + batadv_neigh_node_put(router); + + kref_get(&first_candidate_router->refcount); + router = first_candidate_router; + batadv_last_bonding_replace(orig_node, first_candidate); + } else { + batadv_last_bonding_replace(orig_node, NULL); + } + + /* cleanup of candidates */ + if (first_candidate) { + batadv_neigh_node_put(first_candidate_router); + batadv_orig_ifinfo_put(first_candidate); + } + + if (next_candidate) { + batadv_neigh_node_put(next_candidate_router); + batadv_orig_ifinfo_put(next_candidate); + } + + batadv_orig_ifinfo_put(last_candidate); + + return router; +} + +static int batadv_route_unicast_packet(struct sk_buff *skb, + struct batadv_hard_iface *recv_if) +{ + struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface); + struct batadv_orig_node *orig_node = NULL; + struct batadv_unicast_packet *unicast_packet; + struct ethhdr *ethhdr = eth_hdr(skb); + int res, hdr_len, ret = NET_RX_DROP; + unsigned int len; + + unicast_packet = (struct batadv_unicast_packet *)skb->data; + + /* TTL exceeded */ + if (unicast_packet->ttl < 2) { + pr_debug("Warning - can't forward unicast packet from %pM to %pM: ttl exceeded\n", + ethhdr->h_source, unicast_packet->dest); + goto free_skb; + } + + /* get routing information */ + orig_node = batadv_orig_hash_find(bat_priv, unicast_packet->dest); + + if (!orig_node) + goto free_skb; + + /* create a copy of the skb, if needed, to modify it. */ + if (skb_cow(skb, ETH_HLEN) < 0) + goto put_orig_node; + + /* decrement ttl */ + unicast_packet = (struct batadv_unicast_packet *)skb->data; + unicast_packet->ttl--; + + switch (unicast_packet->packet_type) { + case BATADV_UNICAST_4ADDR: + hdr_len = sizeof(struct batadv_unicast_4addr_packet); + break; + case BATADV_UNICAST: + hdr_len = sizeof(struct batadv_unicast_packet); + break; + default: + /* other packet types not supported - yet */ + hdr_len = -1; + break; + } + + if (hdr_len > 0) + batadv_skb_set_priority(skb, hdr_len); + + len = skb->len; + res = batadv_send_skb_to_orig(skb, orig_node, recv_if); + + /* translate transmit result into receive result */ + if (res == NET_XMIT_SUCCESS) { + ret = NET_RX_SUCCESS; + /* skb was transmitted and consumed */ + batadv_inc_counter(bat_priv, BATADV_CNT_FORWARD); + batadv_add_counter(bat_priv, BATADV_CNT_FORWARD_BYTES, + len + ETH_HLEN); + } + + /* skb was consumed */ + skb = NULL; + +put_orig_node: + batadv_orig_node_put(orig_node); +free_skb: + kfree_skb(skb); + + return ret; +} + +/** + * batadv_reroute_unicast_packet() - update the unicast header for re-routing + * @bat_priv: the bat priv with all the soft interface information + * @skb: unicast packet to process + * @unicast_packet: the unicast header to be updated + * @dst_addr: the payload destination + * @vid: VLAN identifier + * + * Search the translation table for dst_addr and update the unicast header with + * the new corresponding information (originator address where the destination + * client currently is and its known TTVN) + * + * Return: true if the packet header has been updated, false otherwise + */ +static bool +batadv_reroute_unicast_packet(struct batadv_priv *bat_priv, struct sk_buff *skb, + struct batadv_unicast_packet *unicast_packet, + u8 *dst_addr, unsigned short vid) +{ + struct batadv_orig_node *orig_node = NULL; + struct batadv_hard_iface *primary_if = NULL; + bool ret = false; + const u8 *orig_addr; + u8 orig_ttvn; + + if (batadv_is_my_client(bat_priv, dst_addr, vid)) { + primary_if = batadv_primary_if_get_selected(bat_priv); + if (!primary_if) + goto out; + orig_addr = primary_if->net_dev->dev_addr; + orig_ttvn = (u8)atomic_read(&bat_priv->tt.vn); + } else { + orig_node = batadv_transtable_search(bat_priv, NULL, dst_addr, + vid); + if (!orig_node) + goto out; + + if (batadv_compare_eth(orig_node->orig, unicast_packet->dest)) + goto out; + + orig_addr = orig_node->orig; + orig_ttvn = (u8)atomic_read(&orig_node->last_ttvn); + } + + /* update the packet header */ + skb_postpull_rcsum(skb, unicast_packet, sizeof(*unicast_packet)); + ether_addr_copy(unicast_packet->dest, orig_addr); + unicast_packet->ttvn = orig_ttvn; + skb_postpush_rcsum(skb, unicast_packet, sizeof(*unicast_packet)); + + ret = true; +out: + batadv_hardif_put(primary_if); + batadv_orig_node_put(orig_node); + + return ret; +} + +static bool batadv_check_unicast_ttvn(struct batadv_priv *bat_priv, + struct sk_buff *skb, int hdr_len) +{ + struct batadv_unicast_packet *unicast_packet; + struct batadv_hard_iface *primary_if; + struct batadv_orig_node *orig_node; + u8 curr_ttvn, old_ttvn; + struct ethhdr *ethhdr; + unsigned short vid; + int is_old_ttvn; + + /* check if there is enough data before accessing it */ + if (!pskb_may_pull(skb, hdr_len + ETH_HLEN)) + return false; + + /* create a copy of the skb (in case of for re-routing) to modify it. */ + if (skb_cow(skb, sizeof(*unicast_packet)) < 0) + return false; + + unicast_packet = (struct batadv_unicast_packet *)skb->data; + vid = batadv_get_vid(skb, hdr_len); + ethhdr = (struct ethhdr *)(skb->data + hdr_len); + + /* do not reroute multicast frames in a unicast header */ + if (is_multicast_ether_addr(ethhdr->h_dest)) + return true; + + /* check if the destination client was served by this node and it is now + * roaming. In this case, it means that the node has got a ROAM_ADV + * message and that it knows the new destination in the mesh to re-route + * the packet to + */ + if (batadv_tt_local_client_is_roaming(bat_priv, ethhdr->h_dest, vid)) { + if (batadv_reroute_unicast_packet(bat_priv, skb, unicast_packet, + ethhdr->h_dest, vid)) + batadv_dbg_ratelimited(BATADV_DBG_TT, + bat_priv, + "Rerouting unicast packet to %pM (dst=%pM): Local Roaming\n", + unicast_packet->dest, + ethhdr->h_dest); + /* at this point the mesh destination should have been + * substituted with the originator address found in the global + * table. If not, let the packet go untouched anyway because + * there is nothing the node can do + */ + return true; + } + + /* retrieve the TTVN known by this node for the packet destination. This + * value is used later to check if the node which sent (or re-routed + * last time) the packet had an updated information or not + */ + curr_ttvn = (u8)atomic_read(&bat_priv->tt.vn); + if (!batadv_is_my_mac(bat_priv, unicast_packet->dest)) { + orig_node = batadv_orig_hash_find(bat_priv, + unicast_packet->dest); + /* if it is not possible to find the orig_node representing the + * destination, the packet can immediately be dropped as it will + * not be possible to deliver it + */ + if (!orig_node) + return false; + + curr_ttvn = (u8)atomic_read(&orig_node->last_ttvn); + batadv_orig_node_put(orig_node); + } + + /* check if the TTVN contained in the packet is fresher than what the + * node knows + */ + is_old_ttvn = batadv_seq_before(unicast_packet->ttvn, curr_ttvn); + if (!is_old_ttvn) + return true; + + old_ttvn = unicast_packet->ttvn; + /* the packet was forged based on outdated network information. Its + * destination can possibly be updated and forwarded towards the new + * target host + */ + if (batadv_reroute_unicast_packet(bat_priv, skb, unicast_packet, + ethhdr->h_dest, vid)) { + batadv_dbg_ratelimited(BATADV_DBG_TT, bat_priv, + "Rerouting unicast packet to %pM (dst=%pM): TTVN mismatch old_ttvn=%u new_ttvn=%u\n", + unicast_packet->dest, ethhdr->h_dest, + old_ttvn, curr_ttvn); + return true; + } + + /* the packet has not been re-routed: either the destination is + * currently served by this node or there is no destination at all and + * it is possible to drop the packet + */ + if (!batadv_is_my_client(bat_priv, ethhdr->h_dest, vid)) + return false; + + /* update the header in order to let the packet be delivered to this + * node's soft interface + */ + primary_if = batadv_primary_if_get_selected(bat_priv); + if (!primary_if) + return false; + + /* update the packet header */ + skb_postpull_rcsum(skb, unicast_packet, sizeof(*unicast_packet)); + ether_addr_copy(unicast_packet->dest, primary_if->net_dev->dev_addr); + unicast_packet->ttvn = curr_ttvn; + skb_postpush_rcsum(skb, unicast_packet, sizeof(*unicast_packet)); + + batadv_hardif_put(primary_if); + + return true; +} + +/** + * batadv_recv_unhandled_unicast_packet() - receive and process packets which + * are in the unicast number space but not yet known to the implementation + * @skb: unicast tvlv packet to process + * @recv_if: pointer to interface this packet was received on + * + * Return: NET_RX_SUCCESS if the packet has been consumed or NET_RX_DROP + * otherwise. + */ +int batadv_recv_unhandled_unicast_packet(struct sk_buff *skb, + struct batadv_hard_iface *recv_if) +{ + struct batadv_unicast_packet *unicast_packet; + struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface); + int check, hdr_size = sizeof(*unicast_packet); + + check = batadv_check_unicast_packet(bat_priv, skb, hdr_size); + if (check < 0) + goto free_skb; + + /* we don't know about this type, drop it. */ + unicast_packet = (struct batadv_unicast_packet *)skb->data; + if (batadv_is_my_mac(bat_priv, unicast_packet->dest)) + goto free_skb; + + return batadv_route_unicast_packet(skb, recv_if); + +free_skb: + kfree_skb(skb); + return NET_RX_DROP; +} + +/** + * batadv_recv_unicast_packet() - Process incoming unicast packet + * @skb: incoming packet buffer + * @recv_if: incoming hard interface + * + * Return: NET_RX_SUCCESS on success or NET_RX_DROP in case of failure + */ +int batadv_recv_unicast_packet(struct sk_buff *skb, + struct batadv_hard_iface *recv_if) +{ + struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface); + struct batadv_unicast_packet *unicast_packet; + struct batadv_unicast_4addr_packet *unicast_4addr_packet; + u8 *orig_addr, *orig_addr_gw; + struct batadv_orig_node *orig_node = NULL, *orig_node_gw = NULL; + int check, hdr_size = sizeof(*unicast_packet); + enum batadv_subtype subtype; + int ret = NET_RX_DROP; + bool is4addr, is_gw; + + unicast_packet = (struct batadv_unicast_packet *)skb->data; + is4addr = unicast_packet->packet_type == BATADV_UNICAST_4ADDR; + /* the caller function should have already pulled 2 bytes */ + if (is4addr) + hdr_size = sizeof(*unicast_4addr_packet); + + /* function returns -EREMOTE for promiscuous packets */ + check = batadv_check_unicast_packet(bat_priv, skb, hdr_size); + + /* Even though the packet is not for us, we might save it to use for + * decoding a later received coded packet + */ + if (check == -EREMOTE) + batadv_nc_skb_store_sniffed_unicast(bat_priv, skb); + + if (check < 0) + goto free_skb; + if (!batadv_check_unicast_ttvn(bat_priv, skb, hdr_size)) + goto free_skb; + + unicast_packet = (struct batadv_unicast_packet *)skb->data; + + /* packet for me */ + if (batadv_is_my_mac(bat_priv, unicast_packet->dest)) { + /* If this is a unicast packet from another backgone gw, + * drop it. + */ + orig_addr_gw = eth_hdr(skb)->h_source; + orig_node_gw = batadv_orig_hash_find(bat_priv, orig_addr_gw); + if (orig_node_gw) { + is_gw = batadv_bla_is_backbone_gw(skb, orig_node_gw, + hdr_size); + batadv_orig_node_put(orig_node_gw); + if (is_gw) { + batadv_dbg(BATADV_DBG_BLA, bat_priv, + "%s(): Dropped unicast pkt received from another backbone gw %pM.\n", + __func__, orig_addr_gw); + goto free_skb; + } + } + + if (is4addr) { + unicast_4addr_packet = + (struct batadv_unicast_4addr_packet *)skb->data; + subtype = unicast_4addr_packet->subtype; + batadv_dat_inc_counter(bat_priv, subtype); + + /* Only payload data should be considered for speedy + * join. For example, DAT also uses unicast 4addr + * types, but those packets should not be considered + * for speedy join, since the clients do not actually + * reside at the sending originator. + */ + if (subtype == BATADV_P_DATA) { + orig_addr = unicast_4addr_packet->src; + orig_node = batadv_orig_hash_find(bat_priv, + orig_addr); + } + } + + if (batadv_dat_snoop_incoming_arp_request(bat_priv, skb, + hdr_size)) + goto rx_success; + if (batadv_dat_snoop_incoming_arp_reply(bat_priv, skb, + hdr_size)) + goto rx_success; + + batadv_dat_snoop_incoming_dhcp_ack(bat_priv, skb, hdr_size); + + batadv_interface_rx(recv_if->soft_iface, skb, hdr_size, + orig_node); + +rx_success: + batadv_orig_node_put(orig_node); + + return NET_RX_SUCCESS; + } + + ret = batadv_route_unicast_packet(skb, recv_if); + /* skb was consumed */ + skb = NULL; + +free_skb: + kfree_skb(skb); + + return ret; +} + +/** + * batadv_recv_unicast_tvlv() - receive and process unicast tvlv packets + * @skb: unicast tvlv packet to process + * @recv_if: pointer to interface this packet was received on + * + * Return: NET_RX_SUCCESS if the packet has been consumed or NET_RX_DROP + * otherwise. + */ +int batadv_recv_unicast_tvlv(struct sk_buff *skb, + struct batadv_hard_iface *recv_if) +{ + struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface); + struct batadv_unicast_tvlv_packet *unicast_tvlv_packet; + unsigned char *tvlv_buff; + u16 tvlv_buff_len; + int hdr_size = sizeof(*unicast_tvlv_packet); + int ret = NET_RX_DROP; + + if (batadv_check_unicast_packet(bat_priv, skb, hdr_size) < 0) + goto free_skb; + + /* the header is likely to be modified while forwarding */ + if (skb_cow(skb, hdr_size) < 0) + goto free_skb; + + /* packet needs to be linearized to access the tvlv content */ + if (skb_linearize(skb) < 0) + goto free_skb; + + unicast_tvlv_packet = (struct batadv_unicast_tvlv_packet *)skb->data; + + tvlv_buff = (unsigned char *)(skb->data + hdr_size); + tvlv_buff_len = ntohs(unicast_tvlv_packet->tvlv_len); + + if (tvlv_buff_len > skb->len - hdr_size) + goto free_skb; + + ret = batadv_tvlv_containers_process(bat_priv, false, NULL, + unicast_tvlv_packet->src, + unicast_tvlv_packet->dst, + tvlv_buff, tvlv_buff_len); + + if (ret != NET_RX_SUCCESS) { + ret = batadv_route_unicast_packet(skb, recv_if); + /* skb was consumed */ + skb = NULL; + } + +free_skb: + kfree_skb(skb); + + return ret; +} + +/** + * batadv_recv_frag_packet() - process received fragment + * @skb: the received fragment + * @recv_if: interface that the skb is received on + * + * This function does one of the three following things: 1) Forward fragment, if + * the assembled packet will exceed our MTU; 2) Buffer fragment, if we still + * lack further fragments; 3) Merge fragments, if we have all needed parts. + * + * Return: NET_RX_DROP if the skb is not consumed, NET_RX_SUCCESS otherwise. + */ +int batadv_recv_frag_packet(struct sk_buff *skb, + struct batadv_hard_iface *recv_if) +{ + struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface); + struct batadv_orig_node *orig_node_src = NULL; + struct batadv_frag_packet *frag_packet; + int ret = NET_RX_DROP; + + if (batadv_check_unicast_packet(bat_priv, skb, + sizeof(*frag_packet)) < 0) + goto free_skb; + + frag_packet = (struct batadv_frag_packet *)skb->data; + orig_node_src = batadv_orig_hash_find(bat_priv, frag_packet->orig); + if (!orig_node_src) + goto free_skb; + + skb->priority = frag_packet->priority + 256; + + /* Route the fragment if it is not for us and too big to be merged. */ + if (!batadv_is_my_mac(bat_priv, frag_packet->dest) && + batadv_frag_skb_fwd(skb, recv_if, orig_node_src)) { + /* skb was consumed */ + skb = NULL; + ret = NET_RX_SUCCESS; + goto put_orig_node; + } + + batadv_inc_counter(bat_priv, BATADV_CNT_FRAG_RX); + batadv_add_counter(bat_priv, BATADV_CNT_FRAG_RX_BYTES, skb->len); + + /* Add fragment to buffer and merge if possible. */ + if (!batadv_frag_skb_buffer(&skb, orig_node_src)) + goto put_orig_node; + + /* Deliver merged packet to the appropriate handler, if it was + * merged + */ + if (skb) { + batadv_batman_skb_recv(skb, recv_if->net_dev, + &recv_if->batman_adv_ptype, NULL); + /* skb was consumed */ + skb = NULL; + } + + ret = NET_RX_SUCCESS; + +put_orig_node: + batadv_orig_node_put(orig_node_src); +free_skb: + kfree_skb(skb); + + return ret; +} + +/** + * batadv_recv_bcast_packet() - Process incoming broadcast packet + * @skb: incoming packet buffer + * @recv_if: incoming hard interface + * + * Return: NET_RX_SUCCESS on success or NET_RX_DROP in case of failure + */ +int batadv_recv_bcast_packet(struct sk_buff *skb, + struct batadv_hard_iface *recv_if) +{ + struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface); + struct batadv_orig_node *orig_node = NULL; + struct batadv_bcast_packet *bcast_packet; + struct ethhdr *ethhdr; + int hdr_size = sizeof(*bcast_packet); + s32 seq_diff; + u32 seqno; + int ret; + + /* drop packet if it has not necessary minimum size */ + if (unlikely(!pskb_may_pull(skb, hdr_size))) + goto free_skb; + + ethhdr = eth_hdr(skb); + + /* packet with broadcast indication but unicast recipient */ + if (!is_broadcast_ether_addr(ethhdr->h_dest)) + goto free_skb; + + /* packet with broadcast/multicast sender address */ + if (is_multicast_ether_addr(ethhdr->h_source)) + goto free_skb; + + /* ignore broadcasts sent by myself */ + if (batadv_is_my_mac(bat_priv, ethhdr->h_source)) + goto free_skb; + + bcast_packet = (struct batadv_bcast_packet *)skb->data; + + /* ignore broadcasts originated by myself */ + if (batadv_is_my_mac(bat_priv, bcast_packet->orig)) + goto free_skb; + + if (bcast_packet->ttl-- < 2) + goto free_skb; + + orig_node = batadv_orig_hash_find(bat_priv, bcast_packet->orig); + + if (!orig_node) + goto free_skb; + + spin_lock_bh(&orig_node->bcast_seqno_lock); + + seqno = ntohl(bcast_packet->seqno); + /* check whether the packet is a duplicate */ + if (batadv_test_bit(orig_node->bcast_bits, orig_node->last_bcast_seqno, + seqno)) + goto spin_unlock; + + seq_diff = seqno - orig_node->last_bcast_seqno; + + /* check whether the packet is old and the host just restarted. */ + if (batadv_window_protected(bat_priv, seq_diff, + BATADV_BCAST_MAX_AGE, + &orig_node->bcast_seqno_reset, NULL)) + goto spin_unlock; + + /* mark broadcast in flood history, update window position + * if required. + */ + if (batadv_bit_get_packet(bat_priv, orig_node->bcast_bits, seq_diff, 1)) + orig_node->last_bcast_seqno = seqno; + + spin_unlock_bh(&orig_node->bcast_seqno_lock); + + /* check whether this has been sent by another originator before */ + if (batadv_bla_check_bcast_duplist(bat_priv, skb)) + goto free_skb; + + batadv_skb_set_priority(skb, sizeof(struct batadv_bcast_packet)); + + /* rebroadcast packet */ + ret = batadv_forw_bcast_packet(bat_priv, skb, 0, false); + if (ret == NETDEV_TX_BUSY) + goto free_skb; + + /* don't hand the broadcast up if it is from an originator + * from the same backbone. + */ + if (batadv_bla_is_backbone_gw(skb, orig_node, hdr_size)) + goto free_skb; + + if (batadv_dat_snoop_incoming_arp_request(bat_priv, skb, hdr_size)) + goto rx_success; + if (batadv_dat_snoop_incoming_arp_reply(bat_priv, skb, hdr_size)) + goto rx_success; + + batadv_dat_snoop_incoming_dhcp_ack(bat_priv, skb, hdr_size); + + /* broadcast for me */ + batadv_interface_rx(recv_if->soft_iface, skb, hdr_size, orig_node); + +rx_success: + ret = NET_RX_SUCCESS; + goto out; + +spin_unlock: + spin_unlock_bh(&orig_node->bcast_seqno_lock); +free_skb: + kfree_skb(skb); + ret = NET_RX_DROP; +out: + batadv_orig_node_put(orig_node); + return ret; +} |